Common audio encoding standards, such as MPEG-1, Layer 3, significantly compress audio data. This allows for the transmission and storage of the audio and video data with less bandwidth and memory.
Common audio and video encoding standards, such as MPEG-1, Layer 3 (audio) and MPEG-2, or H.264 (video), significantly compress audio and video data, respectively.
In general, the video encoding standards operate on the pictures forming the video. A video comprises a series of pictures that are captured at time intervals. When the pictures are displayed at corresponding time intervals in the order of capture, the pictures simulate motion.
Generally, audio signals are captured in frames representing particular times. During playback, the frames are played at corresponding time intervals in the order of capture. In multi-media applications, it is desirable to play the audio and video, such that audio frames and pictures that were captured during the same time interval are played at approximately the same time interval.
Encoding standards use time stamps to facilitate playback of audio at appropriate times. A decoder compares the times stamps to a system clock to determine the appropriate portions of the audio and video to play. The time stamps are generally examined prior to decoding, because decoding consumes considerable processing power.
Ideally, the time stamps of incoming frames of audio data lead and have a similar rate of increase with the time reference. In such as case, a decoder can decode, and a buffer can buffer several audio frames in advance of playback.
Where the time stamps associated with the incoming frames rise faster than the time reference, the buffers can overflow, resulting in dropped audio frames. When the time arrives for playing the dropped audio frames, there are no audio frames to play. The dropping of audio frames will result in clicking or popping sounds. The clicking and popping sounds significantly degrade the audio quality.
Where the time stamps associated with the incoming frames rise slower than the time reference, the buffers can underflow. As a result, the audio frames are not available at the time of play.
The foregoing are commonly alleviate by either repeating frames or inserting blank frames. This can result in clicking or popping sounds. The clicking and popping sounds significantly degrade the audio quality.
Further limitations and disadvantages of conventional and traditional systems will become apparent to one of skill in the art through comparison of such systems with the invention as set forth in the remainder of the present application with reference to the drawings.